8
3M™ Bair Hugger™ Warming Unit Model 775 – Service Manual
Testing the Over‑Temperature Detection System
!
Warning:
Do not perform the over-temperature detection system test
while the warming unit is being used for warming therapy.
!
Caution:
Perform all temperature testing of the warming unit with a
3M Model 22110 temperature test unit.
!
Caution:
Connect each warming unit being tested to a separate
power source.
SERVICE FREQUENCY
Every 6 months or 500 hours of use, or whenever service is performed.
TOOLS/EQUIPMENT
Model 22110 temperature test unit
Calibrated thermocouple temperature monitor
Method
Note:
If continuing from the previous section (Calibrating the Operating
Temperature) skip to step 4.
Note:
If the warming unit has been stored at a temperature lower than
20°C, allow it to reach ambient temperature before beginning the test.
1.
Connect the warming unit to a grounded power source. The
warming unit performs a self-test and automatically proceeds to
Standby mode.
2.
Connect the temperature test kit to the hose of the warming unit.
3.
Press the
Ambient
button and allow the warming unit to run for
5 minutes.
NOTE:
Verify warming unit is set to the
high fan
(
)
setting by ensuring
the indicator light by the upper fan is illuminated.
4.
With the warming unit in
Ambient
mode, press the
Alternative Mode
button (See Figure 2. Location of Alternative Mode button on page 7)
and the 43°C button simultaneously for 3 seconds. The warming unit
is now in the
Over‑Temperature Detection
Test mode. In this mode, the
warming unit performs the following tasks:
• Blower remains ON.
• Heater elements turn ON at full power.
•
43°C
indicator light flashes.
• Over-temperature timer activates.
•
OT Test
flashes in the alphanumeric display.
5.
Wait for the warming unit to perform the over-temperature test. When
the test is complete, the warming unit performs the following tasks:
• Heater elements turn OFF.
• Blower continues to operate. (
NOTE:
The blower turns off if an
over-temperature condition occurs during normal use.)
6.
View the alphanumeric display to determine test outcome:
a.
PASS–The warming unit detected an over-temperature
condition within 150 seconds. An alarm sounds for 2 short
beeps. The text “PASS” flashes in the alphanumeric display,
followed by these messages:
i.
OT Test ‑ PASS‑Prx
or
OT Test ‑ PASS‑Dst
ii.
TestTime ‑ XX Secs
iii.
Unplug ‑ To Reset
b.
FAIL–Warming unit did not detect an over-temperature
condition within 150 seconds (time-out failure). An alarm sounds
and the
Fault
indicator light flashes. The text
FAIL
flashes in the
alphanumeric display, followed by these messages:
i.
OT Test ‑ FAIL
ii.
TestTime ‑ 150 Secs
iii.
Unplug ‑ To Reset
Note:
Do not place a warming unit back into service if it fails the
over-temperature test. Contact 3M technical support.
7.
Record the maximum temperature displayed by the test kit.
(Use Maintenance Log on page 17.) If the temperature is outside
the range of 46°C to 56°C, contact 3M technical support for
further instructions.
8.
After the test is complete, allow the warming unit to cool by running it
for at least five minutes.
9.
Unplug the warming unit to reset it to normal operation.
Viewing the Fault Code Log
SERVICE FREQUENCY
As often as necessary.
TOOLS/EQUIPMENT
None required.
METHOD
1.
If your warming unit is already ON, you can access the fault code
log from any operating mode. Otherwise, connect the warming unit
to a grounded power source. The warming unit performs a self-test
and automatically proceeds to Standby mode. Then select any
operating mode.
2.
Press the
Alternative Mode
button (Figure 2. Location of Alternative
Mode button on page 7) and the 32°C button simultaneously for three
seconds. The warming unit is now in Fault Code Log mode. In this
mode, the warming unit performs the following tasks:
a.
Continues to operate in current operating mode.
b.
32°C and 38°C indicator light flashes.
c.
Text
FC(n) XXX
appears in the alphanumeric display.
FC
is
an abbreviation for the phrase fault code
n
represents the
numerical order of the fault code in the log, and
XXX
represents
the code for the fault condition. See page 9 for a list of fault
codes and their meanings.
d.
The time (HH:MM:SS) of each fault appears below
FC(n) XXX
in the alphanumeric display. If the warming unit reaches 100 or
more hours the time only reads hours and minutes.
3.
Press either the
32°C
or
38°C
button to view the next fault code in
the log. The warming unit stores a maximum of 5 fault codes in non
volatile memory.
4.
Press the
Alternative Mode
button to return the warming unit to its
previous operating mode.
Clearing the Fault Code Log
Put the warming unit in
Fault Code
mode by pressing the
Alternative Mode
button and the
32°C
button simultaneously for three seconds; then, press
the
43°C
button.
NOTE:
The fault code log should not be cleared unless instructed to do so
by a 3M representative.
9
GB / 34-8718-8817-7
Fault Code Table
The software will detect and report the following conditions by displaying
the corresponding fault code:
FAULT CONDITION
FAULT CODE
Internal sensor 1 over-temperature condition
001
Hose end sensor 2 over-temperature condition
002
Hose end sensor 3 over-temperature condition
003
Internal sensor 1 shorted
004
Hose end sensor 2 shorted
005
Hose end sensor 3 shorted
006
Hose end sensor 2 open
007
Rapid button press, blower failure,
open thermostat or low wattage heater failure
008
Open thermostat/medium wattage heater failure
009
High wattage heater failure
010
A/D converter timeout
011
A/D startup check failed
012
(Reserved Fault Code)
013
Error in execution loop
014
Timeout on alphanumeric display busy flag clearing
015
RAM corruption in duplicate RAM locations
016
Error in executing a depressed key
017
Stuck key during startup
050
EEPROM is at max # write cycles
051
Non-0 EEPROM byte detected after zeroing
052
EEPROM checksum failure on copy #1
(see page 11)
053
EEPROM compare failure copy #1 to copy #2
054
EEPROM compare failure copy #1 to RAM
055
EEPROM write cycle time out
056
SPI byte transfer time out
057
EEPROM write error when entering standby
059
Real time clock failure
060
Temperature out of range high
070
Temperature out of range low
071
5 V power supply in excess of 5.333 V
100
5 V power supply under 4.667 V
101
Startup test EEPROM error
102
Startup test RAM error
103
Viewing the Hour Meter
SERVICE FREQUENCY
As often as necessary.
TOOLS/EQUIPMENT
None required.
METHOD
1.
If your warming unit is already ON, you can begin the test from
any operating mode. Otherwise, connect the warming unit to a
grounded power source. The warming unit performs a self-test
and automatically proceeds to
Standby mode
. Then select any
operating mode.
2.
Press the
Alternative Mode
button for 3 seconds. (See Figure 2.
Location of Alternative Mode button on page 7.) The warming unit
is now in
Hour Meter Display
mode. In this mode, the warming unit
performs the following tasks:
a.
Continues to operate in current operating mode.
b.
Hours
appears in the alphanumeric display.
c.
Cumulative hours of warming unit operation appear in the
alphanumeric display. The time is displayed in whole hours only.
3.
Wait 60 seconds or press the
Alternative Mode
button to return the
warming unit to its previous operating mode.
Viewing the Operating Timer
To view the amount of time the warming unit has been operating in the
current temperature mode, press and hold the current temperature mode
button for at least 3 seconds. The time is displayed in HH:MM:SS format.
Replacing the Air Filter
SERVICE FREQUENCY
Every 12 months or 500 hours of use.
TOOLS/EQUIPMENT
Replacement air filter
#2 Phillips screwdriver
!
Caution:
Do not attempt to clean the air filter as it may be
contaminated from use. Discard the filter in a manner consistent with
institutional protocol.
Method
1.
Disconnect the warming unit from the grounded power source.
2.
Turn the warming unit upside down.
3.
Remove the 2 screws located in the louvered filter cover.
4.
Lift the filter cover off the warming unit.
5.
Remove the air filter and discard it.
6.
Place the new filter in the filter compartment with the gasket toward
the filter ledge.
7.
Replace the filter cover with the louvers facing the back of the
warming unit.
8.
Replace the 2 screws in the filter cover.
Replacing the Hose
SERVICE FREQUENCY
As needed.
TOOLS/EQUIPMENT
Replacement hose
Needle-nose pliers
Strap wrench
METHOD
Detaching Warming Unit Hose
1.
Disconnect the warming unit from the power source before
replacing hose.
2.
Unscrew the hose collar.
3.
Slide the hose out of the warming unit. The hose will still be attached
to the warming unit by a cable.
4.
By hand or using a needle-nose pliers, carefully detach the cable
connector from the header plug located inside the hose connector
(see Figure 3. Hose replacement).
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